It is. It’s always good talking to artists when they’re Number One because they’re in a strange but magical mental state. It’s like talking to someone when it’s Christmas Day but only for them. How has being Number One changed you as a human being?
Well I’m exactly the same, but I have more friends. My phone rings more nowadays, and I get a lot of texts that are like, ‘hey, I know we didn’t talk in high school, but I just wanna say I’m really proud’. It’s like, ‘okaaay…’.

What sort of person were you at high school?
Well I had an older brother who was popular, so I went in that group – he and I are only a year apart, so we’re very close. When we moved, and started at a new school, he made friends immediately so then I was like ‘hey! I’m his sister!’. And then I became ‘the singer girl’.

But presumably there was a point when you wanted to become known not for who you were, and you created your own identity.Yeah, they called me ‘Trainor’s Sister’. I’d be like, ‘no, it’s Meghan!’. But when I got into music more and they hung out with me more they realised that I was ‘pretty cool’. (Laughs)

You signed your first deal – as a songwriter rather than as a performer – a few years ago, right?
It was just two years ago – I was 18.

It must be flattering to be signed purely on the strength of your songwriting.
Yeah. Just based on the songwriting – I was so happy that I didn’t have to go to college!

And you started getting cuts really quickly?
Well no… I suppose some people wait ten years to get a cut and I did get some in the first few years. It started off with some small stuff in Italy that nobody in America heard about. Then I got that Disney girl cut – Sabrina Carpenter. And then Rascal Flatts.

Did you write ‘All About That Bass’ with a view to someone else recording it?
I went [to the writing session] as a songwriter – I didn’t have a [record] deal, I never thought I’d have one – and I met this songwriter [Kevin Kadish], I was a fan of his. I knew the songs he’d written before. I wanted to show I him I was a cool writer! (Laughs) So I said, ‘man, let’s just write something that’s amazing and fun for the world – let’s not have an artist in mind’. Because if you have an artist in mind, then you’ve got rules – you can’t swear, you can’t talk about boys, whatever. He was like, ‘I’m down’.

And at what point during writing it did you think, ‘this one’s not going somewhere else – this is my song’?
I never really felt like that. I knew it was awesome but we both looked at each other and we were both, like, ‘nobody’s going to cut this. We won’t make any money from it, but that’s okay because it’s our awesome little song that we wrote’. And then for like half a year we pitched it to labels. We were just saying, ‘do you have any artists who could possibly do this, ever?’. And everyone was like, ‘no’. They were like, ‘you’ll have to re-produce it’. Because that’s the demo, what you hear. They were like, ‘re-produce it, make it more pop, there’s no Auto Tune’. It was floating forever. Then at one label, Epic, LA Reid heard it. The A&R – who’s now my A&R! – was playing it in the office. LA Reid was like, ‘who’s that?’ ‘Some Nashville writer.’ ‘Go get her!’ (Laughs)

Bloody hell. And this song that’s sailing to Actual Number One in America is still just the demo?
Yeah! It’s the demo man! He kept the mix of it, which is insane! He just went, ‘master it and put it out!’ I literally only signed in February!

It is an extraordinary piece of music and one of the good things about it is that musically it is fairly sparse. Perhaps if you’d been intending to pitch it to Rihanna or someone it would have had a lot more going on in it, which could have killed the magic.
Or Beyoncé. She would have had a whole band in it and everything. But she is a size two.

When you were pitching it to people who actually turned it down?
It was labels, rather than artists turning it down. I know Beyoncé’s people did say they loved it. The best part now is that they’re all emailing me going, ‘I WANTED THAT SONG!’ I’m like, ‘are you kidding?’.

Do you have the second single lined up?
Yes – it’s called ‘Dear Future Husband’. It’s my lil’ list of things he should probably be aware of if he wants to marry me. (Laughs)

What does he need to know?
You need to take me on a date, bring me flowers every anniversary. Tell me I’m beautiful. Sometimes. If you wanna get the ‘special lovin’’. That’s in the chorus, actually.

Is ‘All About That Bass’ a novelty record?
I mean, I think it’s just a good song. It’s reacting like fire. It’s spreading faster and faster. I mean I knew a lot of girls would like it, but I didn’t realise the WORLD would be calling me within five weeks. There’s certainly some spark about it.

Most people will have first heard the music while also seeing the video. And even from the first line of the first verse – ‘it’s pretty clear, I ain’t no size two’ – it feels like it was written with the intention that it wouldn’t just be an audio hit, but a visual one too. Which is quite an interesting way to approach writing.
Yeah. Someone at my label was saying that it’s not just the song that’s spreading, it’s the video that’s making the song viral. It’s the whole thing put together. That’s so cool. Obviously that’s putting the pressure on me for my next video!

But it feels like it might happen more and more, now that video views count in the charts and can also be monetised. It feels like song and video will be treated as one item more and more. Almost to the point where buying an audio file is like buying the soundtrack to a film.
Yeah. And Instagram is everything! I got the same director, Fatima Robinson, for my next video – she also does all my live shows and she does Pharrell’s stuff. They got me the top dog! She’s the most wonderful person, I love her very much. She’s already like, ‘I know what the next video’s going to be like!’. I’m pumped.

You know how if you listen to music with too much bass, it sounds rubbish? Is there such a thing as too much bass?Sure. I hate sitting in cars with subs, and they rattle your stomach and make you feel sick. I don’t like that. My brother got it in his car, I refused to get in the car with him. He just pumped too much bass.

There are two ‘controversial’ aspects to your single. The first is that a lot of people claim you’re criticising skinny people in a song that’s ostensibly about feeling good about your weight.
Yeah. Oh God man, I don’t criticise skinny people! I would never shame a skinny person! I don’t know who would want to. I guess they stop listening immediately after I say ‘skinny bitches’ and just turn it off. But I say, ‘…just kidding, I know even you think you are fat’. For instance, I have skinny friends and some of them will stand in front of the mirror and go, ‘eugh, I’m just like so big’. And I’m standing there going, ‘JESUS! If you’re big then what am I!?’ That’s not right. So I was just saying that. There was a huge Twitter account that made a blog about ‘this is a body shaming song’. I was like, ‘oh my goodness, okaaay…’ I don’t get it. No, I would never shame a skinny person. It makes no sense.

The other point is that the lines about boys chasing bigger girls, your mum saying boys like more to hold at night and so on, raise the question about why feeling good about yourself should be seen in the context of what men think.
Yeah, I’ve got a lot of feminists tweeting me – ‘why have you got to talk about boys?’. I don’t know, man! I just wrote a fun song about loving your booty and loving your body! I never had a problem getting boys, I still got ’em, I still had fun. I don’t know. My mom never actually said those words, she’s a very shy person.

So, more than anything, this song is actually factually inaccurate.
Yes. But my mom does tell me not to criticise myself – if I’d say, ‘I’m so fat’, she’d tell me not to be silly and that I was beautiful.

Will it be hard for you to get sponsorship deals with clothing companies? Given that you are saying it’s okay for people to take a larger size, meaning that fewer size small garments will be sold, therefore meaning that more material will be used, thus raising the cost of producing the average garment and forcing down profits?(Bemused noise) I haven’t even thought that far ahead! Actually that was one of the first things that came: clothing stores were, like, ‘can we dress you?’ And my management is working out merchandise deals at the moment. But I don’t know that far, it’s only been five weeks! By the way have you got a title for my album? I need it like today.

TODAY?
Yeah. I need to figure it out. I was supposed to have it yesterday but I didn’t, because I panicked.

So the second single is ‘Dear Future Husband’, right?
Well I’ve got an EP that’s coming out, and on it I have a song called ‘Title’. It’s basically about ‘call me your girlfriend, I’m sick of being your boo thing, so call me your girlfriend and give me that title’. So I’ve called the EP ‘Title’. Cos obviously everyone was going, ‘what’s the title’, and I was like, ‘hey, I’m clever, I’m gonna make it this’.

But as for the album, if the second single’s the wedding one then maybe ‘I Do’ would be quite a good title.Oh, that’s nice. [SHE SOUNDS COMPLETELY UNIMPRESSED] Do you know the song ‘Take The A Train’?

No.
You don’t? How OLD are you?

Older than you.
Oh. Well it’s an old jazz song. A huge one. My nickname is M-N-Train. They were thinking ‘Take The M Train’. But I was like, does that sound like a sexual thing?

Have you been through the whole Personal Trainor, Trainor Bra selection of options?(Laughs) Yeah! My fans, they wanted to be called Trainors. I was like, no, that’s not going to work.

But instead they’re called Megatrons which is pretty good.
Yeah, my friend came up with that for me. But then she told me yesterday that I can’t make t-shirts with it on because the Transformers people will come and sue me. So I’ll have to fix that ASAP!